| Ha40 | |
|---|---|
 | |
| Preserved Daimler-Benz DB 601. | |
| Type | PistonV12aircraft engine |
| National origin | Japan |
| Manufacturer | Kawasaki |
| First run | 1930s |
| Major applications | Kawasaki Ki-61 |
| Developed from | Daimler-Benz DB 601 |
TheKawasaki Ha40, also known as theArmy Type 2 1,100 hp Liquid Cooled In-line andHa-60, was a license-builtDaimler-Benz DB 601Aa 12-cylinder liquid-cooled inverted-vee aircraft engine. TheImperial Japanese Army Air Service (IJAAS) selected the engine to power itsKawasaki Ki-61 fighter.
The Daimler-Benz DB 601Aa was a development of the earlierDB 600, with direct fuel injection replacing the carburetor. Like all DB 601s, it had a 33.9-litre displacement. The first prototype with the direct fuel injection was test run in 1935, and an order for 150 engines was placed in February 1937.
A manufacturing license was granted toAichi for the production of this engine for theImperial Japanese Navy as theAtsuta and to Kawasaki for production of this engine for the IJAAS as the Ha40. Under the 1944 Unified System, this engine was re-designated as the Kawasaki Ha-60.
The Kawasaki Ha40 and theAichi Atsuta were based on the engine that powered Germany'sMesserschmitt Bf 109 fighter.[1]
A new high-horsepower narrow-profile engine was required for theKawasaki Ki-64 experimental fighter. The aircraft design called for a narrow-profile fuselage, and the solution that Kawasaki developed was the Ha-201 engine. Although similar to theAichi Ha-70, where twoAichi Atsuta engines, mounted side-by-side behind the cockpit driving a single large propeller — an arrangement already used by the Daimler-Benz DB 606 that powered theHeinkel He 119 reconnaissance monoplane prototypes, and later inspired Japan's ownYokosuka R2Y reconnaissance aircraft from the seventh and eighth He 119 prototypes being sold to Japan in May 1940 — for the Japanese Ki-64, its own powerplant installation design called for the two Kawasaki Ha-40 engines to be separately mounted, one in the aircraft's nose, the other behind the cockpit.
The engines were connected to a common gearbox that was mounted in the nose. The rear engine was connected to the nose-mounted gearbox by a long drive shaft similar to the AmericanBell P-39 Airacobra. The gearbox did not combine the power output of the two engines. Instead, the rear engine drove the forward controllable-pitch propeller, while the front engine independently drove the rearward fixed-pitch propeller.[2]
Data from Francillon, p.119
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